ime/o aggressively short functions are painful to debug, understand, and maintain. When there's a bug in a function you need to go down the call stack to find the offending code and fix it. The files wind up being much larger and harder to navigate, and you wind up needing to use tooling to figure out what is broken and why, as opposed to seeing it on inspection.

imo splitting architecture into functions is more about reusability than some arbitrary metric of "one thing" a function is supposed to do, since you can make that "one thing" as granular as you want and leads to a lot of terrible code.